Probably because you are making consecutive posts in one thread.
It's advisable to just edit the previous post or the OP if no one has replied the thread.
As far as i know, Making one post after the other could easily lead to your newer post getting deleted by the mods.
32. Posting multiple posts in a row (excluding bumps and reserved posts by the thread starter) is not allowed.
Okay. But the purpose of making a new reply is to show the audience that the project is making new progress every week. If you read the post, they are weekly updates about the project.